A subsea well of the type concerned herein will have a wellhead supported on the subsea floor. One or more strings of casing will be lowered into the wellhead from the surface, each supported on a casing hanger. The casing hanger is a tubular member that is secured to the threaded upper end of the string of casing. The casing hanger lands on a landing shoulder in the wellhead, or on a previously installed casing hanger having larger diameter casing. Cement is pumped down the string of casing to flow back up the annulus around the string of casing. Afterward, a packoff is positioned between the wellhead bore and an upper portion of the casing hanger. This seals the casing hanger annulus.
Casing hanger running tools perform many functions such as running and landing casing strings, cementing strings into place, and installing and testing packoffs. Once a packoff is set, it is often tested by applying fluid pressure to an upper side of the packoff. If the packoff has not been properly set, fluid pressure may leak past the annulus packoff, causing the casing to collapse.
A need exists for a technique that ensures that the packoff is pressure tested only when it has been properly set. The following technique may solve one or more of these problems.